Signal modulation apparatus and signal modulation method

Abstract

Provided is a signal modulation apparatus configured to modulate an input signal into a multidimensional QAM signal using multidimensional QAM, in which Multidimensional QAM is QAM in which two-dimensional QAM is configured in a multidimensional manner using a plurality of consecutive time slots, a constellation for multidimensional QAM is part of a combination of a constellation of first two-dimensional QAM, and a constellation of second two-dimensional QAM.

What is claimed is: 
     
       1. A signal modulation apparatus comprising
 a memory configured to store an instruction; and 
 at least one processor configured to execute the instruction to modulate an input signal into a multidimensional Quadrature Amplitude Modulation (QAM) signal using multidimensional QAM, wherein 
 the multidimensional QAM is a QAM in which a two-dimensional M-QAM is configured in a multidimensional manner using a plurality of consecutive time slots, 
 the two-dimensional M-QAM is a QAM in which signal points of signal symbols representing a bit sequence are assigned to a two-dimensional plane with an in-phase axis and a quadrature axis, 
 M is an even power of 2 and is equal to or greater than 64, 
 a constellation for the multidimensional QAM is part of a combination of a first constellation and a second constellation, 
 the first constellation is a constellation of the two-dimensional M-QAM, and 
 the second constellation is a constellation of the following two-dimensional QAM:
   (√{square root over ( M )}−1) 2 −QAM.
 
 
 
     
     
       2. The signal modulation apparatus according to  claim 1 , wherein
 in the constellation for the multidimensional QAM, a layout of the signal points is symmetric with respect to the in-phase axis and symmetric with respect to the quadrature axis. 
 
     
     
       3. The signal modulation apparatus according to  claim 1 , wherein
 the multidimensional QAM signal is a signal selected from a plurality of candidate signals in ascending order of amplitude from a candidate signal having smallest amplitude, and 
 the plurality of candidate signals are signals obtained from the combination of the first constellation and the second constellation. 
 
     
     
       4. The signal modulation apparatus according to  claim 1 , wherein
 in the constellation for the multidimensional QAM, a first part of the signal points of one constellation of the first constellation and the second constellation is present on the in-phase axis, and 
 a second part of the signal points of the one constellation is present on the quadrature axis. 
 
     
     
       5. The signal modulation apparatus according to  claim 4 , wherein
 the at least one processor is configured to optimize occurrence probability of each of the signal points in the constellation for the multidimensional QAM in terms of amplitude of the multidimensional QAM signal by using an autoencoder. 
 
     
     
       6. A signal modulation apparatus comprising:
 a memory configured to store an instruction; and 
 at least one processor configured to execute the instruction to modulate an input signal into a multidimensional Quadrature Amplitude Modulation (QAM) signal using multidimensional QAM, wherein 
 the multidimensional QAM is a QAM in which a two-dimensional N-QAM is configured in a multidimensional manner using a plurality of consecutive time slots, 
 the two-dimensional N-QAM is a QAM in which signal points of signal symbols representing a bit sequence are assigned to a two-dimensional plane with an in-phase axis and a quadrature axis, 
 N is an odd power of 2 and is equal to or greater than 32, 
 a constellation for the multidimensional QAM is part of a combination of a first constellation and a second constellation, 
 the first constellation is a constellation of the two-dimensional N-QAM, and 
 the second constellation is a constellation of the following two-dimensional QAM: 
 
       
         
           
             
               
                 
                   ( 
                   
                     
                       
                         N 
                         2 
                       
                     
                     + 
                     1 
                   
                   ) 
                 
                 2 
               
               - 
               QAM 
             
           
         
       
     
     
       7. The signal modulation apparatus according to  claim 6 , wherein
 in the constellation for the multidimensional QAM, a layout of the signal points is symmetric with respect to the in-phase axis and symmetric with respect to the quadrature axis. 
 
     
     
       8. The signal modulation apparatus according to  claim 6 , wherein
 the multidimensional QAM signal is a signal selected from a plurality of candidate signals in ascending order of amplitude from a candidate signal having smallest amplitude, and 
 the plurality of candidate signals are signals obtained from the combination of the first constellation and the second constellation. 
 
     
     
       9. The signal modulation apparatus according to  claim 6 , wherein
 in the constellation for the multidimensional QAM, a first part of the signal points of one constellation of the first constellation and the second constellation is present on the in-phase axis, and 
 a second part of the signal points of the one constellation is present on the quadrature axis. 
 
     
     
       10. The signal modulation apparatus according to  claim 9 , wherein
 the at least one processor is configured to optimize occurrence probability of each of the signal points in the constellation for the multidimensional QAM in terms of amplitude of the multidimensional QAM signal by using an autoencoder. 
 
     
     
       11. A signal modulation method comprising:
 modulating an input signal into a multidimensional Quadrature Amplitude Modulation (QAM) signal using multidimensional QAM; and 
 outputting the multidimensional QAM signal, wherein 
 the multidimensional QAM is a QAM in which a two-dimensional M-QAM is configured in a multidimensional manner using a plurality of consecutive time slots, 
 the two-dimensional M-QAM is a QAM in which signal points of signal symbols representing a bit sequence are assigned to a two-dimensional plane with an in-phase axis and a quadrature axis, 
 M is an even power of 2 and is equal to or greater than 64, 
 a constellation for the multidimensional QAM is part of a combination of a first constellation and a second constellation, 
 the first constellation is a constellation of the two-dimensional M-QAM, and 
 the second constellation is a constellation of the following two-dimensional QAM:
   (√{square root over ( M )}−1) 2 −QAM